How can i fix my Mitsubishi 32" CS-32307 keeps shutting off?

My CS-32307 32" tv has been shutting off by itself lately. I noticed a couple of times the screen got really bright just before. After it has powered down, when I press the power button the light lights up and you hear all the relays clicking on and the picture tube starting up. After about 3 seconds, it clicks off. The only way I can get it back on is to wait for a very long time (hours). Unplugging and plugging it back in doesn't make a difference either. Other than that, everything else on the tv works perfectly, beautiful picture and sound, no discoloration or dead pixels. Also, the tv is connected to a theater pc through the S-VIDEO input. I don't use the built in tuner. The video card outputs the video refresh rate at 60hz